 package cn.edu.ujn.intercepetor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import cn.edu.ujn.dao.User;

public class LoginInterceptor implements HandlerInterceptor{
     @Override
     public boolean preHandle(HttpServletRequest request, 
             HttpServletResponse response, Object handler)
             throws Exception {
         // 获取请求的URL
         String url = request.getRequestURI();
         // URL:除了登录请求外，其他的URL都进行拦截控制
         if (url.indexOf("/login.action") >= 0) {
             return true;
         }
         // 获取Session
         HttpSession session = request.getSession();
         User user = (User) session.getAttribute("USER_SESSION");
         // 判断Session中是否有用户数据，如果有，则返回true,继续向下执行
         if (user != null) {
             return true;
         }
         // 不符合条件的给出提示信息，并转发到登录页面
         request.setAttribute("msg", "您还没有登录，请先登录！");
         request.getRequestDispatcher("/WEB-INF/jsp/login.jsp")
                                                 .forward(request, response);
         return false;
     }
     @Override
     public void postHandle(HttpServletRequest request, 
             HttpServletResponse response, Object handler,
             ModelAndView modelAndView) throws Exception {
     }
     @Override
     public void afterCompletion(HttpServletRequest request, 
             HttpServletResponse response, Object handler, Exception ex)
             throws Exception {
     }

 }

